Field of the Invention
The present invention relates to assistive technologies and more particularly to document ordering for assistive technologies.
Description of the Related Art
In human-computer interaction, computer accessibility refers to the accessibility of a computer system to all end users irrespective of any disability or physical impairment. Accessibility reflects the notion that all end users ought to enjoy fluid access to digital content by way of a computing device despite any physical impairment of the end user such as a visual impairment, aural impairment, or tactile impairment. In particular, to the extent that much of the modern user interface relies upon each of the human tactile, visual and aural senses, a physical impairment of any of those sense, in the absence of a remedial user interface technology, can result in the inability of the impaired individual to interact with the user interface. Remedial technologies designed to overcome the impairment of an end user in respect to the tactile, aural or visual senses are known as “assistive technologies”.
The venerable screen reader represents one popular assistive technology. A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen of a computer, though as it will be apparent, the presence of a display of a computer is not consequential for the visually impaired end user when the computer has been supplemented by a screen reader. This interpretation produced by the screen reader then is re-presented to the user through the means of text-to-speech (TTS), sound icons, or a Braille output device. Screen readers are a form of assistive technology useful not only to the those who are visually impaired to the extent of blindness, but also to those who are visually impaired to a degree where vision is substantially inhibited but not foreclosed, and also to those who are illiterate or learning disabled. To wit, the screen reader can be combined with other technologies such as screen magnifiers so as to facilitate comprehension of a user interface.
Screen readers process content differently depending upon the nature of the content. In the context of Web content, screen readers most commonly “read” the content of a Web page in an order defined by a document object model (DOM) underlying the Web content. However, as a matter of best practices, it is industrially accepted that if a Web page can be navigated sequentially and the navigation sequences of the Web page affect meaning or operation, focusable components should receive focus in an order that preserves meaning and operability. This is not limited to focus navigation as assistive technologies also follow the logical flow of the document itself when browsing a web page, independent of focus navigation. Consequently, the Web page should be navigated by the screen reader in an order corresponding to the navigation sequence of the Web page. Additionally, mobility impaired users who are dependent on focus navigation will also be confused when the visual rendering of the focus sequence does not follow a logical document order. It is for these reasons that accessibility standards require that a document enable the ability to follow a logical navigation order.
Web content can incorporate meta-data so as to facilitate the sequence of presentation by a screen reader. In the hypertext markup language (HTML) version 5 specification, the “aria-flowto” property defines a logical reading order of a page configured for interaction with an assistive technology such as a screen reader. Likewise, the “draw:nav-order” tag defines a logical ordering of presentation in an open document format (ODF) compliant document. The portable document format (PDF) also provides for a tagging mechanism to specify a display order of components of a document. In each case, an assistive technology such as a screen reader can process the meta-data in order to determine an order in which to present content of a document.
Plainly, embedding sequencing meta-data in a document can be a laborious task. To facilitate the process, document editors can provide authoring tools for manual placing sequencing tags within a document. However, the utilization of authoring tools can be complicated and beyond the technical comprehension of most end users. Further, permitting a tech savvy end user to place navigation sequencing meta data into a document can frustrate the intent of the author of the document with respect to the sequencing of the presentation of content in the document. As such, content authors are generally compelled to create two versions of a document—a primary version and a version for processing with an assistive technology.